Metering member for a seed meter

ABSTRACT

A metering member for a seed meter having a with a sidewall formed with an radially outward and axially flared rim portion is provided. A plurality of apertures extend though the rim portion to which seed is adhered. The metering member is oriented at an angle to the vertical such that an upper portion of the metering member extends beyond a lower portion of the metering member. This orientation allows a seed delivery system to extend into the interior of the metering member and cooperate with the overhanging metering member to remove seed therefrom.

FIELD

The following relates to an air pressure differential seed meter and inparticular to a metering member for a seed meter.

BACKGROUND

Various types of seed meters have been developed that use an airpressure differential, either vacuum or positive pressure, to adhereseed to a metering member. The metering member takes seed from a seedpool and sequentially discharges single seeds. (In some cases, multipleseeds may be discharged at a time.) One common type of seed meter isshown in U.S. Pat. No. 5,170,909. There, a seed disk 48 contained in ahousing is used to meter the seed. The seed pool is positioned on oneside of the disk at a lower portion thereof while vacuum is applied tothe opposite side of the disk. As the disk is rotated, individual seedsfrom the seed pool are adhered by the vacuum to apertures that extendthough the disk. When the seed reaches a desired release position, thevacuum is terminated, allowing the seed to drop from the disk, through aseed tube to a furrow formed in the soil below.

Flexible belts have also been used in an air pressure differential seedmeter. One example is shown in US patent application 2010/0192818 A1.There, a flexible belt having an array of apertures therein is movablealong a path in a housing. A seed pool is formed on one side of thebelt. Vacuum applied on the opposite side of the belt along a portion ofthe belt path adheres seed to the apertures, allowing the belt to movethe seed to a release position where the vacuum is cut-off. The seedthen falls or is removed from the belt.

When seed falls by gravity from the meter through the seed tube, it canbe difficult to maintain accurate and consistent seed spacing atplanting speeds greater than about 8 kph (5 mph). To maintain spacingaccuracy, a seed delivery system that controls the seed as the seedmoves from the seed meter to the soil is desirable. One such deliverysystem is shown in US patent application 2010/0192819-A1. With such adelivery system, the hand-off of seed from the disk of U.S. Pat. No.5,170,909 to the delivery system is difficult to achieve in a consistentmanner. While the hand-off of seed may be improved with the use of abelt meter, there is still a need for a more consistent and reliablehand-off of seed from the seed meter to the delivery system. An improvedseed meter and seed metering member can improve the hand-off of seed tothe delivery system.

SUMMARY

A metering member for an air pressure differential seed meter isprovided having a bowl shaped body having a base portion and a sidewallextending from the base portion. The sidewall terminates in an outeredge and has an inner surface and an outer surface. The sidewall furtherhas a rim portion adjacent the outer edge that extends radiallyoutwardly and axially with a plurality of apertures extending throughthe sidewall.

The metering member cooperates with a seed delivery system that movesseed from the metering member to the soil.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a common agricultural planter;

FIG. 2 is a side perspective view of a planting unit frame, seed meterand seed delivery system;

FIG. 3 is an enlarged perspective view of the seed meter and deliverysystem drives;

FIG. 4 is a perspective view of the seed meter with the cover openillustrating the metering member;.

FIG. 5 is an exploded perspective view of the seed meter of FIG. 4;

FIG. 6 is a perspective view of the metering member of FIG. 4;

FIG. 7 is side cross-section of the metering member of FIG. 6illustrating the orientation of the metering member installed in a seed,meter mounted to a planting unit;

FIG. 8 is a fragmentary cross-section of an alternative metering member;

FIG. 9 is a elevational view of the inside of the metering member ofFIG. 6;

FIG. 10 is a side sectional view of the metering member and seeddelivery system;

FIG. 11 is a sectional view of the hand-off of seed from the meteringmember to the delivery system including the delivery system brush belt;

FIG. 12 is a sectional view like FIG. 11 without the delivery systembrush belt;

FIG. 13 is a schematic illustration the direction of entry of seed intothe brush belt;

FIG. 14 is a schematic illustration of the direction of travel of theseed on the metering member and in the delivery system at the releaseposition of seed from the metering member;

FIG. 15 is side sectional view of the metering member and deliverysystem at the hand-off without the brush belt;

FIG. 16 is a perspective view of the inner side of the seed meterhousing;

FIG. 17 is a side sectional view of the metering member and meterhousing illustrating the seed pool formed by the metering member andhousing;

FIG. 18 is side sectional view like FIG. 17 illustrating a prior at seedmeter with a disk metering member;

FIG. 19 is a perspective view of the lower end of the delivery system;and

FIGS. 20 and 21 are perspective views of an alternative metering member.

DETAILED DESCRIPTION

An agricultural seeding machine 10 is shown in FIG. 1 as a row cropplanter.

Seeding machine 10 has a central frame 12 on which are mounted aplurality of individual planting units 14. The seeding machine 10 has afore-aft direction shown by the arrow 15 and a transverse directionshown by the arrow 17. Each planting unit 14 is coupled to the centralframe 12 by a parallel linkage 16 so that the individual planting units14 may move up and down to a limited degree relative to the frame 12.Large storage tanks 13 hold seed that is delivered pneumatically to amini-hopper on each planting unit. Each planting unit 14 has a framemember 18 (FIG. 2) to which the components of the planting unit aremounted. The frame member 18 includes a pair of upstanding arms 20 atthe forward end of thereof. The arms 20 are coupled to the rearward endsof the parallel linkage 16. Furrow opening disks (not shown) areattached to shaft 22 in a known manner to form an open furrow in thesoil beneath the seeding machine into which seed is deposited. Closingand packing wheels (not shown) are also mounted to the frame member 18in a known manner to close the furrow over the deposited seed and tofirm the soil in the closed furrow. A seed meter 24 and a seed deliverysystem 400 are also attached to the frame member 18 of the plantingunit.

The meter 24 includes a housing 30 (FIG. 3) and a cover 34. The housing30 and the cover 34 are coupled to one another by complementary hingefeatures 36. and 38 (see FIG. 5) on the housing and cover respectively.Hinge feature 36 includes a pivot pin 37 coupled to the housing whilethe feature 38 is an integrally formed hook that wraps around the pivotpin allowing the cover 34 to pivot about the axis of the pin 37. Anelastomeric latch member 40 is coupled to the housing 30 and has anenlarged portion 42 that is seated into a socket 44 formed in the coverto hold the cover in a closed position on the housing 30.

The housing 30 is formed with a second hinge element in the form of apivot pin 46 (FIG. 3). Pivot pin 46 is seated into a hook member 48(FIG. 4) of the mounting frame 50 attached to the frame member 18. Thisallows the seed meter 24 to pivot relative to the planting unit framemember 18 about an axis 52. A drive spindle 54 is carried by the housing30 and has a drive hub 56 (FIG. 5) on the end thereof. The spindle 54couples to the output shaft 58 of electric motor 60 to drive the seedmeter when in the assembled position shown in FIG. 3. The seed meter 24is coupled to the delivery system by a latch mechanism 68 including ametal rod 70 having a hook at one end seated into an aperture in themeter housing 30 when latched. The delivery system further has amounting hook 72, partially shown in FIG. 2, which attaches to theplanting unit frame member 18 to support the delivery system.

The delivery system 400 is driven by an electric motor 80, also carriedby the mounting frame 50. The output shaft of motor 80 is connected tothe delivery system through a right-angle drive 82. While electricmotors have been shown to drive both the seed meter and the seeddelivery system, it will be appreciated by those skilled in the art thatother types of motors, such as hydraulic, pneumatic, etc. can be used aswell as various types of mechanical drive systems.

With reference to FIG. 6, a metering member 100 of the seed meter isshown in greater detail. These metering member 100 is shown as a singlepiece, concave bowl shaped body. The bowl shaped body has a base portion102 from which extends a sidewall 104. Sidewall 104 terminates in anouter edge 106. The sidewall has a radially inner surface 108 and aradially outer surface 110. Adjacent the outer edge 106, the sidewallhas a rim portion 112 shown by the bracket in FIG. 6. The rim portion112 extends radially outwardly and axially toward the outer edge 106. Inthe rim portion 112, there is an annular array of apertures 114 thatextend through the sidewall between the inner and outer surfaces 108 and110. The metering member 100 is mounted in the meter housing forrotation in the direction of the arrow 118 in FIG. 6. In operation, asthe metering member rotates, individual seeds from a seed pool 120located at a bottom portion of the metering member are adhered to theapertures 114 on the inner surface 108 of the sidewall and sequentiallycarried upward to a release position 164 at an upper portion of themetering member. Thus, the inner surface is also known as the seed sideof the metering member. A series of raised features or projections, suchas paddles 116, extend from the inner surface 108 of the sidewall 104typically with one paddle located behind each aperture 114 in thedirection of rotation. Each paddle forms a confronting surface 124behind the associated aperture in the direction of rotation to push theseed adhered to the aperture into the delivery system as describedbelow. As explained above, it is the rim portion 112 of the meteringmember that performs the function of drawing individual seeds from theseed pool and sequentially moving seed to the release position to supplyseed individually to the seed delivery system 400.

The base portion 102 of the metering member contains a central driveaperture 130 (FIG. 5) used to mount the, metering member on a rotationaldrive hub. 56 for rotation about the axis 132 in a manner similar tomounting a flat seed disk in a seed meter as is well known. When mountedto the housing 30, the metering member 100 cooperates with the housingto form a trough to hold the seed pool 120 as described more fullybelow. The axis 132 is inclined to both a horizontal plane as well as toa vertical plane extending fore and aft of the seeding machine and avertical plane extending transversely to the seeding machine.

With reference to FIG. 7, the metering member 100 is shown in asectional view. The base portion 102 is a generally planar while the rimportion 112 of the inner surface of the sidewall 104 is outwardlyflared, that is, extending both radially outward and axially. As shownin FIG. 7, the rim portion is frusto-conical. Alternatively, as shown inFIG. 8 in connection with a metering member sidewall 104′, the innersurface of the sidewall rim portion 112 may be frusto-spherical inshape. Furthermore, while the rim portion 112 has been shown as beingoutwardly flared, the rim portion could be generally cylindrical withoutany outward flair, that is, extending only axially.

The metering member 100 can be formed as one piece or constructed ofmultiple pieces. The metering member can be most easily molded ofplastic such as polycarbonate, nylon, polypropylene or urethane.However, other plastics can be used as well as other materials such asmetal, etc. The metering member 100 is sufficiently rigid to beself-sustaining in shape without additional supporting structure. Thisis in contrast to the flexible belt metering member shown in U.S. Pat.No. 2,960,258 where it be belt member is preferably of a flexibleelastomeric material and is supported within a support ring. Beingself-sustaining in shape; the metering member does hot need anysupporting structure to: hold a shape. As a self-sustaining, themetering member may be rigid or the metering member may be flexible tochange shape when acted upon in a manner similar to the flexible seeddisk of U.S. Pat. No. No. 7,661,377.

As previously mentioned, the metering member 100 can be mounted to adrive hub through the central drive aperture 130 in the base portion102. Mounting through the central drive aperture 130 provides bothmounting support of the metering member as well as the rotational driveof the metering member. Alternatively, support for the metering membercan be provided on the outer surface of the sidewall. A groove may beformed in the outer surface of the sidewall to receive rollers thatsupport the metering member. If the groove is also formed with driveteeth, one of the rollers could be driven by a motor to rotate themetering member. With such alternative arrangements possible, it is notnecessary that the metering member have a base portion. The function ofmetering seed is performed by the sidewall and thus, the sidewall is theonly required portion of the metering member.

As shown in FIG. 7, the metering member 100, when mounted in the meterhousing, is oriented at an incline to the vertical as shown. In thisorientation, the apertures 114 lie in a plane 150 inclined at an angle arelative to vertical. In this orientation, an upper portion 148 of themetering member overhangs or extends beyond a lower portion 154. Asdescribed below, this allows access to the upper portion 148 of themetering member for the mechanical seed delivery system 400. As shown,the angle α is approximately 24°. However, any angle will suffice aslong as the upper portion 148 extends beyond the lower portionsufficiently for access for the seed delivery system from below themetering member at the seed release position.

The seed pool 120 is formed at the bottom of the metering member 100 asshown in FIG. 9. Vacuum is applied to the outer surface 110, causingindividual seeds to be adhered to the apertures 114 as the aperturestravel through the seed pool. As the metering member rotates as shown bythe arrow 118, seed is moved upward to a release position 164 at theupper portion 148 of the metering member. The release position isslightly past the top or 12 O'clock position on the circular path oftravel of the seed such that the seed is moving somewhat downward at therelease position. This facilitates the seed's entry into the deliverysystem as more fully described below. Also, by being past the top pointof the path, the delivery system is off center relative to the meteringmember providing clearance between the delivery system and the seedmeter drive. At the release position 164, the inner surface of the rimportion of the metering member is facing downward such that seed isadhered beneath the metering member or is hanging from the meteringmember. See FIG. 10. The seed delivery system 400 is also positionedbeneath the upper portion of the metering member at the release position164 to take the seed from the metering member as shown in FIG. 10.

Delivery system 400 includes a housing 402 having a left sidewall 404(see FIG. 19) and a right sidewall 406 (see FIG. 3). The terms left andright are used in relationship to the direction of travel of the seedingmachine shown by the arrow 408. Connecting the left and right sidewallsto one another is an edge wall 410. An upper opening 416 is formed inthe edge wall and sidewalls to allow seed to enter into the housing 402.A lower opening 418 is provided at the lower end forming a dischargelocation 413 for the seed. A pair of pulleys 420 and 422 are mountedinside the housing 402. The pulleys a support a belt 424 for rotationwithin the housing. One of the two pulleys is a drive pulley while theother pulley is an idler pulley. The belt has a flexible base member 426to engage the pulleys. Elongated bristles 428 extend from the basemember 426. The bristles are joined to the base member at proximal, orradially inner, ends of the bristles. Distal, or radially outer, ends430 of the bristles touch or are close to touching the inner surface ofthe housing edge wall 410.

As shown at the top of FIG. 10, a seed 152 is at the release position onthe metering member 100 and has just been inserted into the bristles 428of the delivery system. At the release position, the rim portion 112 ofthe metering member sidewall 104 is generally tangent to the stationaryinner surface 412 across which the brush bristles 428 sweep. The surface412 is on a latch portion 66 of the housing 30. The surface 412 is acontinuation of the inner surface 414 of the delivery system housing402. Once the seed is captured in the delivery system, the seed moves inthe direction of the belt, shown by the arrow 417. The direction oftravel of the seed immediately upon capture by the delivery system 400is shown by the vector 438.

Prior to release of the seed from the metering member, the seed ismoving in the direction of vector 160 which is slightly downward intothe bristles 428. With reference to FIG. 13, the vector 160 of the seeddirection is at an angle 161 of about 60° to the length of the bristles428 shown by the arrow 176. As shown in FIG. 11, the brush belt ispositioned so that seed enters the bristles at the corner of the brushbelt. The brush can be positioned so that the seed enters the brushthrough the distal ends of the bristles or through the side of thebristles.

The relationship between the seed direction vector 160 on the meteringmember and the seed direction vector 438 when the seed is first in thebrush belt is shown in FIG. 14 illustrating the two vectors in the planecontaining both vectors at the release position 164. The angle 163between the vectors is at least 35° and preferably between 50° and 80°.This shows the cross-feed of the seed into the bristles, meaning thatthe seed, prior to the release position is moving substantially in adifferent direction than the brush bristles are moving. This is incontrast to the arrangement shown in FIG. 3 of the previously mentionedUS patent application 2010/0192819-A1 where the seed on the meteringdisk at the release is moving in substantially the same direction as thebrush bristles. This is also the relationship by which the bristlessweep over the inner surface of the sidewall relative to the traveldirection of seed.

FIGS. 11 and 12 show a blocking member 162 carried by the meter housing30. Blocking member 162 is positioned adjacent a path of travel of seed152 leading to the release position 164 and prevents movement of seedfrom the metering member prior to reaching the release, position. Oncethe seed has passed the end 174 of the blocking member 162, the seed isfree to move with the brush bristles in the direction of the vector 438in FIG. 10. The blocking member ensures that the seed is consistentlyfeed into the brush belt in the center of the belt, widthwise, ratherthan allowing the seed to enter the belt at random positions across thebelt width. As shown in FIG. 15, the blocking member is located beneaththe sidewall 104 of the metering member 100 between the paddles 116 andthe outer edge 106 of the metering member. The confronting surfaces 124of the paddles 116 push seed into the brush bristles. The paddles orprojections 116 travel further into the brush bristles, that is deeperinto the bristles from their distal ends, as the projections cross thewidth of the brush as seen in FIG. 11. Once seed is in the brushbristles, the seed is swept over the inner surface of the meteringmember, from the apertures 114 to the outer edge 106 of the meteringmember in the direction of the vector 438. The delivery system could bearranged to sweep seed in the opposite direction, that is, away from theouter edge 106 of the metering member.

To further ensure consistent release of seed from the metering memberand hand-off to the delivery system, an ejector 166, carried by thecover 34 rides on the outer surface of the metering member rim portion.See FIGS. 11, 12 and 15. The ejector 166 is in the form of a star wheelhaving a number of projections 168. The projections 168 extend into theapertures 114 from the outer surface 110 of the sidewall 104 and forceseed out of the apertures 114. The ejector is caused to rotate byrotation of the metering member 100 due to the projections 168 engagingin the apertures 114. The ejector is mounted to the cover 34 via a pivotarm 170 and bracket 171. The ejector 166 is biased against the meteringmember by a spring 172.

Turning attention once again to FIG. 4, a flexible seal 180 is shown onthe inner side of the cover 34. This seal bears against the outersurface 110 of the metering member 100 forming a vacuum chamber withinthe interior 182 of the seal. A first portion 184 of the seal is spacedradially further out on the metering member than is the second portion186 of the seal. In the area of the seal first portion 184, vacuum isapplied to the apertures 114, causing seed to adhered thereto. There isno vacuum applied to the apertures adjacent and outside of the sealsecond portion 186. A port 188 in the cover 34 is adapted to connect theinterior of the cover to a vacuum source in a known manner for a vacuumseed meter. The seed release position 164 is within the vacuum chamber.Thus, the brush belt and the ejector are working in opposition to thevacuum applied to the apertures 114 to release the seed from themetering member.

With reference to FIG. 16, The inside of the housing 30 is shown. Thehousing includes a central boss 302 for the drive spindle 54. Thehousing also includes an opening 304 to receive seed from a mini-hopper,not shown, mounted to the outside of the housing and surrounding theopening 304. Below the opening 304, the housing wall forms a ramp 306extending downward toward the lower end 308 of the housing. The rampcooperates with the inner surface 108 of the metering member to hold theseed pool 120. The housing includes an inward projection 310 forming acavity 314 (FIG. 17) on the outside of the housing into which the upperend if the delivery system 400 is placed. The projection is open at theupper end, forming a downward looking opening 312 from the interior ofthe housing to the exterior. This opening 312 allows the brush belt 424to access the inner surface of the 108 of the metering member and carryseed from the housing.

FIG. 17 illustrates the orientation of the metering member and thecooperation of the housing 30 and metering member 100 to form a troughfor the seed pool 120 at the lower end of the metering member. FIG. 17shows the orientation of the metering member when the seeding machine 10is on level ground. At the lower end of the metering member, thesidewall 104 is inclined to the vertical such that the inner surface 108is at an angle d to the vertical vector 126. As illustrated in FIG. 17,the inner surface is approximately 21° from vertical. The orientation ofthe housing adjacent the metering member, forming the other side of thetrough, is not critical. Seed from the seed pool 120 sits on top of theinner surface 108 and a component of the force of gravity isperpendicular to the inner surface 108. When operating on a hillside, ifthe meter is tilted clockwise or counter-clockwise, as viewed in FIG.17, the inner surface 108 remains inclined and gravity still has acomponent perpendicular to the inner surface. This is in contrast to atypical disk seed meter shown in FIG. 18 with a vertically oriented disk320 cooperating with a housing wall 322 for form a seed pool 324. Ifthis meter is tilted counterclockwise as viewed, seed from the pool willstill bear against the disk. However, if the meter is tilted clockwise,seed from the pool will fall away from the disk, allowing for decreasedmetering performance in terms of seed being picked-up by the disk.Evaluation of the meter has shown improved meter performance on ahillside when the angle d is as small as 5° and as large as 75°. Betterperformance is achieved when the angle d is between 10° and 50° whilethe optimum performance is in the range of 20° to 40°. This last rangeprovides considerable tilting of the seed meter on a hillside in anydirection before performance begins to decrease.

At the upper end of the metering member, at the release position 164,the inner surface 108 has an angle f to a downward vertical vector 128in the range of 50° to 90° with the closer to 90° being the better forhand-off of seed from the metering member to the brush belt. As shown,the angle f is approximately 68°. The different orientations of theinner surface 108 relative to vertical at the seed trough and at therelease position is accomplished with a metering member that is rigid.Such variation is not possible with the flat disk metering member shownin FIG. 18.

As described above, seed is adhered to the apertures 114 in the meteringmember due to the vacuum applied to the outer surface of the meteringmember creating a pressure differential on opposite sides of themetering member. As an alternative to vacuum on the outer side of themetering member, the pressure differential can be created by a positivepressure between the housing 30 and the metering member 100. Such asystem would require seals between the metering member 100 and thehousing 30 to create a positive pressure chamber. In a positive pressurearrangement, the cover 34 only serves as a cover for the rotatingmetering member.

It is possible that more than one seed will, be adhered to a givenaperture 114. To prevent more than one seed at a time from beingtransferred to the brush belt, a pair of doubles eliminators orsingulating members are attached to the housing 30 along the path ofseed from the seed pool to the release position 164. The singulatingmembers are in the form of brushes 330 and 332 (FIGS. 5 and 9). Brush330 has bristles extending substantially axially and brushes seed on theapertures 114 by extending inwardly from the outer edge 106 of themetering member. The bristles of brush 330 are of varying length, toengage the seed at several discrete locations along the length of thebrush 330. The brush 332 has bristles extending substantially radiallyand engaging the inner surface of the metering member sidewall inside ofthe paddles 116 and extend along the sidewall to the apertures 114. Bothbrushes 330, and 332 act to slightly disturb seed on the aperture andcause excess seed to fall off. Once removed, the excess seed falls backto the seed pool 120. The brushes can be fixed in position or they canbe adjustable to change the degree to which the brushed disturb seed onthe metering member. A third brush 334 is shown which extends generallyradially of the metering member. The brush 334 serves to define aboundary to the seed pool 120. The brushes 330, 332 and 334 are mountedto the housing 30.

Returning again to FIG. 10, once seed is captured or trapped in thebristles 428, the delivery system controls the movement of seed from theseed meter to the discharge location. The seeds are held in the bristlessuch that the seeds can not move vertically relative to the bristles 428or relative to other seeds in the delivery system. Particularly, duringtravel of the seeds along the vertical side of the delivery system, theseeds are held on at least the top and bottom of the seeds to preventany relative movement between the seed and the brush belt. Thus, therelative position of the seeds to one another is not affected bydynamics of the planting unit while moving across a field. The seed iscarried by the bristles from the upper opening 416 to the lower opening418 with the movement of the seed controlled at all times from the upperopening to the lower opening.

The lower opening 418 of the delivery system housing is positioned asclose to the bottom 446 of the seed trench or furrow 448 as possible. Asshown, the lower opening 418 is near or below the soil surface 432adjacent the seed furrow. The bottom of the delivery system should be nomore than one or two inches, (2.5-5 cm) above the soil surface 432. Ifpossible, the lower end of the delivery system should be below the soilsurface 432. The housing edge wall 410 forms an exit ramp 434 at thelower opening 418. The lower opening 41$ and the ramp 434 are positionedalong the curve in the belt path around the pulley 422. The seed, beingcarried by the bristle's distal ends, increases in linear speed aroundthe pulley 422 as the distal ends of the bristles travel a greaterdistance around the pulley 422 than does the base member 426 of thebelt. This speed difference is shown by the two arrows 440 and 442.

At discharge, the seed has a velocity shown by the vector V. Thisvelocity has a vertical component V_(V) and a horizontal componentV_(H). The belt is operated at a speed to produce a horizontal velocitycomponent V_(H) that is approximately equal to, but in the oppositedirection of, the seeding machine forward, velocity shown by arrow 408.As a result, the horizontal velocity of the seed relative to the groundis zero or approximately zero. This minimizes rolling of the seed in theseed trench.

Seed can be inserted into the brush bristles at essentially an infinitenumber of positions. This enables the brush to be operated at the speednecessary to produce the desired horizontal velocity component to theseed, independent of the seed population. The seed meter, on the otherhand, must be operated at a speed that is a function of both the forwardtravel speed of the seeding machine and the desired seed population.Because the belt 424 can be loaded with seed at essentially an infinitenumber of positions, the belt speed can be operated independently of theseed meter speed. This is not the case with other seed delivery systems,such as that disclosed in U.S. Pat. No. 6,681,706 where the deliverysystem of FIG. 2 has a belt with flights to carry the seed. The beltspeed must be timed to the seed meter speed to ensure that one or moreflights pass the seed meter for each seed that is discharged from themeter.

While it is desirable to match the seed rearward velocity to the seedingmachine forward velocity to minimize seed relative velocity to the soil,with some seed types, it may be necessary to operate the brush belt at adifferent speed to ensure the seed is discharged from the brushbristles.

The interior of the lower portion of delivery system housing is shown inFIG. 19. The delivery system housing 402 is a two-piece housing havingan upper housing member 460 and a lower housing member 462. The lowerhousing member carries the lower pulley 422. The lower housing memberhas an upwardly extending rod portion 464 that slides within a channelformed by walls 466 and 468 in the upper housing member. Springs, notshown, push downward on the rod portion 464 to bias the lower housingmember downward. The brush belt 424, wrapped about the pulleys 420 and422, holds the upper and lower housing, members together. The belt 424is tensioned by the springs acting on the rod portion 464. A U-shapedmetal strip 470 is attached to the upper housing member 460 and bridgesthe gap 472 between the upper and lower housing members to provide acontinuous surface for holding seed in the housing between the upperopening 416 and the lower opening 418. The metal strip has a tab at theupper end thereof bent over and inserted into a slot 474 in the upperhousing member 460 to hold the metal strip 470 in place. If needed, afastener, such as a nut and bolt, may be placed through the rod portion464 and the upper housing member 460 to fix the upper and lower housingmembers together.

Different metering members may be used for different seed types. Themetering member 100 is intended for soybeans and other crops plantedwith a fairly close seed spacing. Corn, which is planted at a greaterseed spacing uses a metering member 200 shown in FIGS. 20 and 21.Metering member 200 is constructed in a similar fashion as meteringmember 100 and like components are given the same reference numeral withthe addition of 100. However, metering member 200 has half the number ofapertures 214 as the metering member 100. To avoid the need to replacethe ejector 166 when changing metering members, the metering member 200has recess 226 extending into the sidewall 204 on the outer surface 210of the sidewall between each aperture 214. The recesses 226 provideclearance for the projections 168 of the ejector 166 that are arrangedto be inserted in each aperture 114 of the metering member 100. Therecesses 226 are not open to the inner surface 208 of the sidewall 204.Thus there are additional projections 228 on the inner surface of thesidewall 204 between the apertures 214. Alternatively, the projections228 and the paddles 216 can be formed as a single projections extendingfrom the inner surface 208.

Having described the seed meter and delivery system, it will becomeapparent that various modifications can be made without departing fromthe scope of the accompanying claims.

1. A metering member for an air pressure differential seed metercomprising: a bowl shaped body having a base portion and a sidewallextending axially and radially outwardly from the base portion, thesidewall terminating in an outer edge and having an inner surface and anouter surface and the sidewall further having a rim portion adjacent theouter edge with a plurality of apertures extending through the sidewall.2. The metering member of claim 1 wherein the rim portion of thesidewall is frusto-conical.
 3. The metering member of claim 1 whereinthe rim portion of the sidewall is frusto-spherical.
 4. The meteringmember of claim 1 further comprising at least one projection extendinginwardly from the inner surface of the sidewall forming a confrontingsurface following at least one aperture in a direction of rotation ofthe metering member.
 5. The metering member of claim 1 furthercomprising a recess extending into the sidewall on the outer surface ofthe sidewall between each aperture.
 6. A metering member for an airpressure differential seed meter comprising: a concave bowl shaped bodyhaving a base portion; a sidewall extending from the base portion andterminating in an outer edge, the sidewall having an inner surface andan outer surface, the sidewall including a rim portion adjacent theouter edge extending radially and axially outwardly with a plurality ofapertures extending through the rim portion of the sidewall; and aplurality of projections extending inwardly from the inner surface ofthe sidewall forming a confronting surface following each aperture in adirection of rotation of the metering member.